Certain 2-benzimidazole carbamates and their utility

ABSTRACT

WHEREIN R1 and R2 can be the same or different and are selected from alkyl, aryl, haloalkyl, cycloalkyl, alkenylaryl, and furanyl. The compositions described herein are useful as fungicides and biocides.   New compounds corresponding to the formula

United States Patent Baker [451 Sept. 19, 1972 CERTAIN Z-BENZIMIDAZOLE CARBAMATES AND THEIR UTILITY [72] Inventor: Don R. Baker, Orinda, Calif.

[73] Assignee: Staufler Chemical Company, New

York, NY.

221 Filed: Sept. 25,1970

211 Appl.No.: 75,753

[52] US. Cl ..260/240 J, 424/273, 260/309.2

[51] Int. Cl. ..C07d 49/38 [58] Field of Search ..260/240 .1, 309.2

[56] References Cited Primary Examiner-John D. Randolph Attorney-Daniel C. Block, Edwin H. Baker, Albert J. Adamcik and Harry A. Pacini [57] ABSTRACT New compounds corresponding to the formula wherein R, and R, can be the same or different and are selected from alkyl, aryl, haloalkyl, cycloalkyl, alkenylaryl, and furanyl. The compositions described herein are useful as fungicides and biocides.

CERTAIN 2-BENZIMIDAZOLE CARBAMATES AND THEIR UTILITY DESCRIPTION OF THE INVENTION The present invention is concerned with a novel group of compounds which can be generally described as 2-benzimidazole carbamates, and their use as pesticides, especially effective against fungi and parasites.

The compounds are represented by the general formula Ql-Rr 1 1 wherein R, and R, can be the same or different and can A mixture of 9.6 grams (0.05 moles) of 2- benzimidazole methyl carbamate, 100 ml. of chloroform and 12.5 grams cyclopropane carboxylic acid chloride was formed. Then, 17 ml. of triethylamine was added dropwise with stirring over a period of 30 minutes at l8-20 C. and the mixture stirred at room temperature for 18 hours. The solution was washed with 100 ml. water, dried over MgSO. and evaporated in vacuo to yield an oil that crystallized from cold ethyl ether to yield 13 grams of crystals after air drying. M.p. l08 1 09 C.

EXAMPLE lll Other compounds were prepared in an analogous manner starting with the appropriate starting materials, as outlined above. The following is a table of compounds representative of those embodied by the present invention. Compound numbers have been assigned to them and are used for identification o be selected from alkyl, aryl, haloalkyl, cycloalkyl, althroughout the balance ofthevspec'ficat'on" kenylaryl, and furanyl. TABLE 1 The compounds represented by the above general formula are manufactured by reacting a 2- L benzimidazole alkyl carbamate in an inert solvent with an acid chloride or other like material in the presence N of an acid acceptor. The inert solvent can be selected L from benzene, chloroform, or the like. The acid accep- I tor can be selected from triethylamine, pyridine, or the 11 like. In order to illustrate the merits of the present in- 0 vention, the following examples are provided. comp 1 EXAMPLEI 1 T W T W Preparation of i i 0 2 {i-CHr-CH: I 0 a CII=CH clr==cr r y -N' I =N (LL' CH 4 02H C2115 ,L a omcmci omcmcl v V V 6 CH2 CH2 A mixture of 9.6 grams (0.05 moles) of 2- (L (i benzimidazole methyl carbamate, 100 ml. of CH1 chloroform and 10.5 ml. (0.12 moles) of propionyl 7-.. CH3 CH3 chloride was prepared. Then, 16.8 ml. of triethylamine in 30 ml. of chloroform was added to the mixture with stirring over a period of 1 hour and 40 minutes at 22-26 C. The mixture was stirred for 30 minutes and then washed with I00 ml. of water, dried over MgSO. and evaporated in vacuo to yield an oil that crystallized from ethyl ether to yield 10.2 grams of solid with m.p. of l03-l05 C.

EXAMPLE II FUNGICIDE TESTING PROCEDURES chamber and held until disease pustules appear on the leaves. Effectiveness is recorded as percent reduction in number of pustules as compared to untreated inoculated plants.

2. Bean Powdery Mildew Test chemicals are prepared and applied in the same manner as for the bean rust test. After the plants are dry, the leaves are dusted with spores of the powdery mildew fungus (Erysiphe polygoni De Candolle)v and the plants are retained in the greenhouse until the fungal growth appears on the leaf surfaces. Effectiveness is recorded as percent of the leaf surface free of fungal growth as compared to untreated inoculated plants. B. Tube Systemic Test 1. Bean Rust The chemicals are dissolved in an appropriate solvent and diluted with tap water to a series of descending concentrations beginning at 50 ppm. Sixty ml. of each concentration are placed in a test tube. A pinto bean plant is placed in each tube and supported with a piece of cotton so that only the roots and lower stem are in contact with the test solution. Forty-eight hours later the bean leaves are inoculated with a water suspension of spores of the bean rust fungus and placed are prepared. Aliquots of the toxicant, dissolved in an appropriate solvent, are injected through the stopper, into the broth, to provide concentrations ranging from 50 ppm downward. The test organisms consist of two fungi, Aspergillus niger (A.n.) van Tieghem and Penicil- Iium ilalicum (P.i.) Wehmer, and two bacteria, Escherichia coli (E.c.) Migula and Staphylococcus aureus (S.a.) Rosenbach. Three drops of a spore suspension of each of the fungi are injected into the tubes of malt broth and three drops of the bacteria are injected into the nutrient broth. One week later the growth of each organism is observed and effectiveness of the chemical is recorded as the lowest concentration in ppm which provides 50 percent inhibition of growth as compared to untreated inoculated tubes.

The results of the above tests are set forth in the following table.

TABLE II Preventative sprays, ppm. Tube systemic,

In vitro vinl (p.p.m.) Rust Mildew p.p.iu.

("ompouud Number .A.u. l.i. Em. S '1 1, 000 500 100 1, 000 500 100 50 25 1O Rust Mildew 5 0.03 50 50 75 5O 100 100 100 100 100 75 6 0. 13 0.03 50 550 100 95 75 100 100 100 100 100 100 5 0.13 0. 13 50 50 95 50 0 100 100 90 50 1. Oi) 1 0. 02 50 50 100 100 80 100 100 100 1 0. 06 50 l. 00 50 50 25 5 5 O. 06 50 50 5 0. 13 1 0. 02 50 50 100 100 100 100 100 85 1 0. 06

in an environment with 100 percent humidity for 24 hours. The plants are then removed from the humidity chamber and maintained in the greenhouse until the disease pustules appear on the leaves. Effectiveness is recorded as the lowest concentration, in ppm, which will provide 50 percent reduction in pustule formation as compared to untreated, inoculated plants.

2. Bean Powdery Mildew Test chemicals are prepared and applied in the same manner as for the bean rust systemic test. After 2 daysthe leaves are dusted with spores of the powdery mildew fungus and maintained in the greenhouse until mycelial growth appears on the leaf surfaces. Effectiveness is recorded as the lowest concentration, in ppm, which will provide a 50 percent reduction in mycelial growth on the leaf surface as compared to untreated, inoculated plants.

BIOCIDE TESTING PROCEDURES Tubes of sterilized nutrient and malt extract broth What is claimed is:

l. A compounds corresponding to the generic formula 

2. The compound as set forth in claim 1 wherein R1 and R2 are furanyl.
 3. The compound as set forth in claim 1 wherein R1 and R2 are styryl. 